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July 1, 2013

Observing Live Gene Expression In The Body

by editor

A team from UNIGE has developed a biotechnology that can be used in many biomedical sectors

Most of our physiological functions fluctuate throughout the day. They are coordinated by a central clock in the brain and by local oscillators, present in virtually every cell. Many molecular gearwheels of this internal clock have been described by Ueli Schibler, professor at the Faculty of Science of the University of Geneva (UNIGE), Switzerland. To study how the central clock synchronizes subordinate oscillators, the researcher's group used a variety of genetic and technological tools developed in collaboration with a team of UNIGE physicians. In this way, the scientists were able to directly observe the bioluminescence emitted by 'clock genes' in mice for several months. This biotechnology is applicable to numerous sectors of biomedical research, which attracted the attention of the editors from the journal "Genes & Development".

In mammals, there are many behaviors and biological functions that are regulated by internal clocks. Most of our cells have one, made from a family of 'clock genes', whose cyclic activity reaches a specific peak in 24 hours. These local oscillators are synchronized by a central 'pacemaker' in the brain which adjusts to light.

In collaboration with the University of Ulm and the Center for Integrative Genomics (CIG) of Lausanne, the biologists studied how the central clock synchronizes subordinate oscillators in mice. Various clock genes, coupled with the luciferase gene for light emission, were inserted into liver cells using a molecular vector. The time these rodents spent in the bioluminescent device allowed to demonstrate that the central clock generates signals, some of which act directly on the liver oscillators, and others which synchronize them indirectly by controlling the cycles of food intake.

â¦or the effect of a medication in mice

'This technology enables a drastic reduction in the number of mice needed for this type of experiment, and furthermore, it is applicable to many areas of biomedical research,' says Camille Saini, researcher in the Department of Molecular Biology at UNIGE and first author of this article. These complementary genetic and engineering technology tools could be used to directly follow certain biochemical effects of metabolites like cholesterol or glucose, as well as the response to potential treatments of diseases such as hypercholesterolemia or diabetes. Monitoring the response to various hormones, neurotransmitters and other biochemical messengers is also part of this application range.